Radiation curable compositions produced by the reaction of an organic polyisocyanate, an hydroxyalkyl acrylyl compound and a polyhydroxyl compound are known. Thus, in U.S. Pat. No. 3,700,643 issued on Oct. 24, 1972 to Smith et al there are disclosed the reaction products of an organic polyisocyanate, an acrylyl compound and a polyfunctional polycaprolactone. In U.S. Pat. No. 3,509,234 issued on Apr. 28, 1970 to Burlant et al there are disclosed reaction products in which different types of polyfunctional organic polymers are reacted with the organic polyisocyanate and acrylyl compounds. Further, in U.S. Pat. No. 3,297,745 issued on Jan. 10, 1967 to Fekete et al there are disclosed the reaction products of an organic diisocyanate with an ethylenically unsaturated alcohol, which can be an hydroxyalkyl acrylyl compound, with a polyol optionally being present.